Panel product

ABSTRACT

A decorative panel product formed through compressing and consolidating a mat of loosely organized, bondable wood particles. The panel includes a medial portion having one thickness and one density, and a marginal portion having a substantially lesser thickness and a greater density than the medial portion. The panel&#39;&#39;s marginal portion is slotted, whereby a pair of spaced substantially parallel flanges are defined which can be squeezed toward one another to facilitate fitting the extremities of the marginal portion into grooves in a supporting framework.

United States Patent [7 2] Inventor Charles Herbert Warwick Eugene,Oreg. [21] Appl. No. 723,797 [22] Filed Apr. 24, 1968 [45] Patented Oct.26, 1971 [73] Assignee Fibreboard Corporation San Francisco, Calif.

[54] PANEL PRODUCT 4 Claims, 3 Drawing Figs.

[52] 11.8. C1 161/44, 161/87, 161/149, 161/162, 52/595 [51] Int. Cl B32b1/04, E04c 1/ 10 [50] Field of Search 161/44, 56,87,112,109,166,149,124,162;52/475,595

[56] References Cited UNITED STATES PATENTS 1,465,383 8/1923 Walsh etal.161/56 2,224,209 12/1940 Allen 161/44 2,642,371 6/1953 Fahrni 161/1622,975,089 3/1961 Hargreaves... 161/124 3,485,519 12/1969 Chiu 52/475Primary Examiner--Douglas J. Drummond Alt0rney- Kolisch & Hartwellmeasrsgzmargg PATENTEDUU 26 mm 3, 616, 12 0 BY M VHM,

A TTOP/VE/f PANEL PRODUCT This invention relates to a decorative panelwhich is formed from consolidated, fibrous, lignocellulose particles.

There is a demand for decorative panels of the type having pronouncedthree-dimensional facial (i.e., nonuniformthickness) characteristics,such as by including a raised island, either plain or embossed, disposedinwardly of panel margins. In the past, such panels have typically beenproduced from lumber which is milled to have the desired finalconfiguration. Such a procedure is expensive, requires technical skillto perform, and is time consuming. Further, the product produced, whenprepared from a grained board, is subject to splitting.

A general object of the present invention is to provide a noveldecorative panel, having facial features of the type generallyindicated, which can be produced in a manner avoiding the drawbacks justmentioned.

More specifically, an object of the invention is to provide such a panelwhich can be manufactured in a relatively simple and inexpensive mannerfrom lignocellulose particles, with molding of the design desired in theface of the panel.

Another object is to provide a panel which is not subject to splitting.Also, the panel features margins compressed to high density which may beused in mounting.

According to a preferred embodiment of the invention, the proposed panelis formed from a mat of loosely organized wood particles which have beentreated with a suitable adhesive. The that includes a core layer ofrelatively coarse particles, and opposed surface layers disposed onopposite sides of the core layer containing finer particles. Theparticles in the mat are consolidated in a single pressing step toproduce a panel having a medial portion with one thickness and onedensity, and a marginal portion extending about the medial portion witha substantially lesser thickness and greater density than the medialportion. The coarse particles of the core layer contribute to strengthin the panel. The fine particles of the surface layers contribute tosmooth outer surfaces in the panel.

Yet another object of the invention is to provide a panel of the typedescribed which is easy to install in a panel-supporting framework. Thepanel-supporting members in such a framework typically include groovesfor receiving the outer extremities of a panel. Obviously, it isdesirable that a panels extremities fit snugly within such grooves, butnot so snugly as to make it difficult to install the panel. To insure aproper fit, and to facilitate installation, the marginal portion of theproposed panel is slotted to define a pair of spaced flanges in themarginal portion. During installation of a panel, such flanges may besqueezed together to simplify fitting the outer extremities ofthemarginal portion in a groove.

These and other objects and advantages attained by the invention willbecome more fully apparent as the description which follows is read inconjunction with the accompanying drawings, wherein:

FIG. I is a fragmentary front elevation illustrating a portion of a doorcontaining a panel constructed according to the invention;

FIG. 2 is a front elevation of the panel of FIG. 1, with the panelremoved from the door; and

FIG. 3 is an enlarged cross-sectional view taken along the line 3-3 inFIG. ll.

Turning now to the drawings, indicated generally at in FIG. I is aportion of a door. The door includes upright, laterally spaced stiles,such as stiles 12, 14, joined by transversely extending, verticallyspaced rails, such as rails l6, 18. The stiles and rails may be made ofwood. Mounted on these stiles and rails, and also forming part of thedoor, is a rectangular panel constructed according to the invention.

Referring to FIGS. 1, 2 and 3, panel 20 is a unitary structure includinga medial portion 22 having a thickness A, and a marginal portion 24having a considerably lesser thickness B. In the panel illustrated,dimension A may be about one'half inch, and dimension B may be aboutone-quarter inch. Portions 22, 24 join one another trough a taperedregion 26. As can be seen in FIG. 3, the marginal portion is bounded byopposed outer faces disposed intermediate the planes of opposite sidesof the medial portion.

Further describing panel 20, marginal portion 24 extends in fourexpanses along each edge of the panel. Each expanse comprises a pair ofspaced flanges 28, 30 separated by a slot 32. The base or floor 27 ofslot 32 lies in tapered region 26. With the flanges being resilientlyyieldable the flanges may be squeezed toward one another to reduce theoverall thickness of the outer extremities of the marginal portion.

Panel 20 is supported in the door with the outer extremities of marginalportion 24 fitted snugly within elongated grooves provided in the stilesand rails. More: specifically, and con sidering the part of the marginalportion which is illustrated in FIG. 3, the outer extremity thereof isreceived within a groove 34 in stile 14. Groove 34 has a width W whichis slightly less than dimension B. As a consequence, flanges 28, 30which normally occupy the dash dot outline positions shown at 28A, 30Ain FIG. 3, occupy the solid outline positions shown where they aresqueezed toward one another.

Considering the internal construction of the panel, it comprises threelayers 36, 38, 40 of consolidated and bonded wood particles. Layer 36constitutes a core layer in the panel, and contains relatively coarseparticles. Layers 38, 40 may be somewhat thinner than layer 36, andconstitute surface layers in the panel. These layers may containparticles of finer size. The density in marginal portion 24 isconsiderably greater than the density in medial portion 22. Slot 32 isin a region disposed intermediate layers 38 and 40 where such layersextend into the marginal portion.

Describing now how a panel such as panel 20 may be formed, a particleboard furnish may b prepared from wood particles, such as Douglas firchips, having the following screen analysis: +4 mesh, 1.0%; +I0 mesh,26.0%; +20 mesh, 34.0%; +35 mesh, 21.0%; +48 mesh, 11.0%; 48 mesh, 7.0%.A suitable resin binder, such as any of the various well-knownthermosetting urea formaldehyde or pheno-formaldehyde resins, may thenbe distributed in the furnish. Preferably, the distributed resin shouldconstitute approximately 6% by weight of the final mixture of furnishand resin.

The resin-coated particles in the furnish may then be prepared into amat including a core layer containing the relatively coarse particles insuch furnish, sandwiched between surface layers of finer particles insuch furnish (48 mesh or less). This may be accomplished by usingwell-known gravity separating techniques now employed in the particleboard industry. The overall thickness of the mat prepared, of course,will vary depending upon the thickness desired in the final boardproduct. By way of example, to prepare a panel having the dimensionsindicated above for panel 20, a mat of approximately 2 /-inch thicknessmight be prepared. In such a mat, the core layer of relatively coarseparticles might have a thickness of about 2 inches, and each surfacelayer of fine particles a thickness of about one-quarter inch.

The particles in the mat may then be consolidated in a press to producea structure including medial and marginal portions having the respectivethicknesses and facial characteristics described above for panel 20.MOre specifically, consolidation may be accomplished by a pair ofopposing platens in the press which are shaped to produce such facialcharacteristics. Preferably, during the consolidation step, the press isheated to a temperature ranging from about 225 F. to 400 F. tofacilitate curing of the resin distributed! in the mat.

In panels prepared in the manner just described and having thedimensions indicated, the medial portions thereof had a density rangingfrom about 45-50 lbs/ft. and the marginal portions had a density rangingfrom about 55-albs/ft.

After the pressing operation, the marginal portion of a panel may betrimmed to have the desired outside dimensions. The marginal portion maythen be slotted as by cutting a kerf with a saw. Preferably, in a panelwherein the marginal portion is about one-quarter inch thick, the slotcut therein has a width of about one-sixteenth inch, and extendsinwardly from the periphery of the marginal portion to the region wherethe marginal and medial portions join.

The invention thus provides a novel decorative panel which can be formedin a relatively simple and convenient manner from consolidated,bonded-together wood particles. With relatively fine particles employedin the portion of the panel adjacent its opposite faces, such faces havea smooth surface, which, for most purposes, requires no sanding. Withthe configurations of the opposing faces produced as the result of apressing operation, rather than as the result of milling, considerablesimplification in manufacturing and economies are realized.

Because the panel is formed from consolidated particles held together bya binder, the panel constitutes a unitary structure which possesses goodstrength characteristics. The relatively high density provided in themarginal portion facilitates cutting a slot therein.

With the slots described extending along the four expanses of marginalportion 24, and because the flanges which are produced by preparing theslots are resiliently yieldable to a degree, mounting of the panel in asupporting framework is considerably simplified. A snug fit can beproduced which extends uniformly about the panel. Note also that it isusual when compressing a particle board panel to compress to apredetermined density rather than to a predetermined thickness. With thethickness of the mat subject to some slight variation during itspreparation, this means that after the mat is formed under pressure, thethickness of the marginal expanse produced may be subject to some slightvariation. By including the slots contemplated, greater tolerances arepermitted in the thickness of the marginal expanses, as well as in thewidths of the slots in the framework that receive such marginalexpanses.

While a preferred embodiment of the invention has been described, it isappreciated that variations and modifications are possible withoutdeparting from the invention. It is desired to cover all suchmodifications and variations which would be apparent to one skilled inthe art and that come within the scope ofthe appended claims.

It is claimed and desired to secure by letters patent:

l. A unitary panel having predetermined nonuniformthicknesscharacteristics, said panel being formed from tion and extending alongan edge of the panel, said marginal portion having a substantiallylesser thickness and a greater density than said medial portion.

2. A unitary panel having predetermined nonuniformthicknesscharacteristics, said panel being formed from bonded ligno-celluloseparticles which have been pressureconsolidated to produce the panel withsaid characteristics therein, and which particles are distributed inplural interlocked layers, with each layer extending substantiallycontinuously across the panel, and with said layers including a corelayer containing particles larger than 48 mesh in size, and a pair ofsurface layers on opposite sides of said core layer containing particlesno larger than 48 mesh in size, said panel comprising a medial portionhaving one'thickness and one density, and

a marginal portion formed integrally with said medial portion andextending along an edge of the panel, said marginal portion having asubstantially lesser thickness and a greater density than said medialportion, and comprising a pair of laterally spaced, substantiallyparallel flanges defining between them a slot which extends along theedge of the fhe panel of claim 2, wherein said slot extends inwardlyfrom the periphery of said marginal portion to a base which is adjacentthe outer extremity of said medial portion.

4. The panel of claim 2, wherein the marginal portion is bounded byopposed outer faces disposed intermediate the planes of opposite sidesof said medial portion.

2. A unitary panel having predetermined nonuniform-thicknesscharacteristics, said panel being formed from bonded ligno-celluloseparticles which have been pressure-consolidated to produce the panelwith said characteristics therein, and which particles are distributedin plural interlocked layers, with each layer extending substantiallycontinuously across the panel, and with said layers including a corelayer containing particles larger than 48 mesh in size, and a pair ofsurface layers on opposite sides of said core layer containing particlesno larger than 48 mesh in size, said panel comprising a medial portionhaving one thickness and one density, and a marginal portion formedintegrally with said medial portion and extending along an edge of thepanel, said marginal portion having a substantially lesser thickness anda greater density than said medial portion, and comprising a pair oflaterally spaced, substantially parallel flanges defining between them aslot which extends along the edge of the panel.
 3. The panel of claim 2,wherein said slot extends inwardly from the periphery of said marginalportion to a base which is adjacent the outer extremity of said medialportion.
 4. The panel of claim 2, wherein the marginal portion isbounded by opposed outer faces disposed intermediate the planes ofopposite sides of said medial portion.